cregit-Linux how code gets into the kernel

Release 4.9 arch/x86/kernel/dumpstack.c

Directory: arch/x86/kernel
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/utsname.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/ftrace.h>
#include <linux/kexec.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/sysfs.h>

#include <asm/stacktrace.h>
#include <asm/unwind.h>


int panic_on_unrecovered_nmi;

int panic_on_io_nmi;

unsigned int code_bytes = 64;

int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;

static int die_counter;


bool in_task_stack(unsigned long *stack, struct task_struct *task, struct stack_info *info) { unsigned long *begin = task_stack_page(task); unsigned long *end = task_stack_page(task) + THREAD_SIZE; if (stack < begin || stack >= end) return false; info->type = STACK_TYPE_TASK; info->begin = begin; info->end = end; info->next_sp = NULL; return true; }

Contributors

PersonTokensPropCommitsCommitProp
josh poimboeufjosh poimboeuf82100.00%1100.00%
Total82100.00%1100.00%


static void printk_stack_address(unsigned long address, int reliable, char *log_lvl) { touch_nmi_watchdog(); printk("%s [<%p>] %s%pB\n", log_lvl, (void *)address, reliable ? "" : "? ", (void *)address); }

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PersonTokensPropCommitsCommitProp
neil hormanneil horman3271.11%125.00%
josh poimboeufjosh poimboeuf613.33%125.00%
adrien schildknechtadrien schildknecht511.11%125.00%
jiri slabyjiri slaby24.44%125.00%
Total45100.00%4100.00%


void printk_address(unsigned long address) { pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address); }

Contributors

PersonTokensPropCommitsCommitProp
jiri slabyjiri slaby26100.00%1100.00%
Total26100.00%1100.00%


void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, char *log_lvl) { struct unwind_state state; struct stack_info stack_info = {0}; unsigned long visit_mask = 0; int graph_idx = 0; printk("%sCall Trace:\n", log_lvl); unwind_start(&state, task, regs, stack); /* * Iterate through the stacks, starting with the current stack pointer. * Each stack has a pointer to the next one. * * x86-64 can have several stacks: * - task stack * - interrupt stack * - HW exception stacks (double fault, nmi, debug, mce) * * x86-32 can have up to three stacks: * - task stack * - softirq stack * - hardirq stack */ for (; stack; stack = stack_info.next_sp) { const char *str_begin, *str_end; /* * If we overflowed the task stack into a guard page, jump back * to the bottom of the usable stack. */ if (task_stack_page(task) - (void *)stack < PAGE_SIZE) stack = task_stack_page(task); if (get_stack_info(stack, task, &stack_info, &visit_mask)) break; stack_type_str(stack_info.type, &str_begin, &str_end); if (str_begin) printk("%s <%s> ", log_lvl, str_begin); /* * Scan the stack, printing any text addresses we find. At the * same time, follow proper stack frames with the unwinder. * * Addresses found during the scan which are not reported by * the unwinder are considered to be additional clues which are * sometimes useful for debugging and are prefixed with '?'. * This also serves as a failsafe option in case the unwinder * goes off in the weeds. */ for (; stack < stack_info.end; stack++) { unsigned long real_addr; int reliable = 0; unsigned long addr = READ_ONCE_NOCHECK(*stack); unsigned long *ret_addr_p = unwind_get_return_address_ptr(&state); if (!__kernel_text_address(addr)) continue; if (stack == ret_addr_p) reliable = 1; /* * When function graph tracing is enabled for a * function, its return address on the stack is * replaced with the address of an ftrace handler * (return_to_handler). In that case, before printing * the "real" address, we want to print the handler * address as an "unreliable" hint that function graph * tracing was involved. */ real_addr = ftrace_graph_ret_addr(task, &graph_idx, addr, stack); if (real_addr != addr) printk_stack_address(addr, 0, log_lvl); printk_stack_address(real_addr, reliable, log_lvl); if (!reliable) continue; /* * Get the next frame from the unwinder. No need to * check for an error: if anything goes wrong, the rest * of the addresses will just be printed as unreliable. */ unwind_next_frame(&state); } if (str_end) printk("%s <%s> ", log_lvl, str_end); } }

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PersonTokensPropCommitsCommitProp
josh poimboeufjosh poimboeuf23683.69%233.33%
neil hormanneil horman4114.54%116.67%
namhyung kimnamhyung kim31.06%116.67%
adrien schildknechtadrien schildknecht10.35%116.67%
frederic weisbeckerfrederic weisbecker10.35%116.67%
Total282100.00%6100.00%


void show_stack(struct task_struct *task, unsigned long *sp) { task = task ? : current; /* * Stack frames below this one aren't interesting. Don't show them * if we're printing for %current. */ if (!sp && task == current) sp = get_stack_pointer(current, NULL); show_stack_log_lvl(task, NULL, sp, ""); }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman2548.08%120.00%
josh poimboeufjosh poimboeuf1426.92%360.00%
tejun heotejun heo1325.00%120.00%
Total52100.00%5100.00%


void show_stack_regs(struct pt_regs *regs) { show_stack_log_lvl(current, regs, NULL, ""); }

Contributors

PersonTokensPropCommitsCommitProp
borislav petkovborislav petkov2095.24%150.00%
josh poimboeufjosh poimboeuf14.76%150.00%
Total21100.00%2100.00%

static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; static int die_owner = -1; static unsigned int die_nest_count;
unsigned long oops_begin(void) { int cpu; unsigned long flags; oops_enter(); /* racy, but better than risking deadlock. */ raw_local_irq_save(flags); cpu = smp_processor_id(); if (!arch_spin_trylock(&die_lock)) { if (cpu == die_owner) /* nested oops. should stop eventually */; else arch_spin_lock(&die_lock); } die_nest_count++; die_owner = cpu; console_verbose(); bust_spinlocks(1); return flags; }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman7197.26%150.00%
thomas gleixnerthomas gleixner22.74%150.00%
Total73100.00%2100.00%

EXPORT_SYMBOL_GPL(oops_begin); NOKPROBE_SYMBOL(oops_begin); void __noreturn rewind_stack_do_exit(int signr);
void oops_end(unsigned long flags, struct pt_regs *regs, int signr) { if (regs && kexec_should_crash(current)) crash_kexec(regs); bust_spinlocks(0); die_owner = -1; add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); die_nest_count--; if (!die_nest_count) /* Nest count reaches zero, release the lock. */ arch_spin_unlock(&die_lock); raw_local_irq_restore(flags); oops_exit(); if (!signr) return; if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); /* * We're not going to return, but we might be on an IST stack or * have very little stack space left. Rewind the stack and kill * the task. */ rewind_stack_do_exit(signr); }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman9795.10%125.00%
rusty russellrusty russell21.96%125.00%
andy lutomirskiandy lutomirski21.96%125.00%
thomas gleixnerthomas gleixner10.98%125.00%
Total102100.00%4100.00%

NOKPROBE_SYMBOL(oops_end);
int __die(const char *str, struct pt_regs *regs, long err) { #ifdef CONFIG_X86_32 unsigned short ss; unsigned long sp; #endif printk(KERN_DEFAULT "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter, IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "", IS_ENABLED(CONFIG_SMP) ? " SMP" : "", debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "", IS_ENABLED(CONFIG_KASAN) ? " KASAN" : ""); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP) return 1; print_modules(); show_regs(regs); #ifdef CONFIG_X86_32 if (user_mode(regs)) { sp = regs->sp; ss = regs->ss & 0xffff; } else { sp = kernel_stack_pointer(regs); savesegment(ss, ss); } printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip); print_symbol("%s", regs->ip); printk(" SS:ESP %04x:%08lx\n", ss, sp); #else /* Executive summary in case the oops scrolled away */ printk(KERN_ALERT "RIP "); printk_address(regs->ip); printk(" RSP <%016lx>\n", regs->sp); #endif return 0; }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman16275.35%110.00%
rasmus villemoesrasmus villemoes2612.09%110.00%
h. peter anvinh. peter anvin177.91%110.00%
jan beulichjan beulich41.86%220.00%
christian borntraegerchristian borntraeger20.93%110.00%
andy lutomirskiandy lutomirski10.47%110.00%
srikar dronamrajusrikar dronamraju10.47%110.00%
prarit bhargavaprarit bhargava10.47%110.00%
andrey ryabininandrey ryabinin10.47%110.00%
Total215100.00%10100.00%

NOKPROBE_SYMBOL(__die); /* * This is gone through when something in the kernel has done something bad * and is about to be terminated: */
void die(const char *str, struct pt_regs *regs, long err) { unsigned long flags = oops_begin(); int sig = SIGSEGV; if (!user_mode(regs)) report_bug(regs->ip, regs); if (__die(str, regs, err)) sig = 0; oops_end(flags, regs, sig); }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman7098.59%150.00%
andy lutomirskiandy lutomirski11.41%150.00%
Total71100.00%2100.00%


static int __init kstack_setup(char *s) { ssize_t ret; unsigned long val; if (!s) return -EINVAL; ret = kstrtoul(s, 0, &val); if (ret) return ret; kstack_depth_to_print = val; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman3056.60%150.00%
shuah khanshuah khan2343.40%150.00%
Total53100.00%2100.00%

early_param("kstack", kstack_setup);
static int __init code_bytes_setup(char *s) { ssize_t ret; unsigned long val; if (!s) return -EINVAL; ret = kstrtoul(s, 0, &val); if (ret) return ret; code_bytes = val; if (code_bytes > 8192) code_bytes = 8192; return 1; }

Contributors

PersonTokensPropCommitsCommitProp
shuah khanshuah khan3250.79%150.00%
neil hormanneil horman3149.21%150.00%
Total63100.00%2100.00%

__setup("code_bytes=", code_bytes_setup);

Overall Contributors

PersonTokensPropCommitsCommitProp
neil hormanneil horman65053.50%12.94%
josh poimboeufjosh poimboeuf34228.15%823.53%
shuah khanshuah khan554.53%12.94%
jiri slabyjiri slaby282.30%12.94%
rasmus villemoesrasmus villemoes262.14%12.94%
borislav petkovborislav petkov201.65%12.94%
h. peter anvinh. peter anvin171.40%12.94%
masami hiramatsumasami hiramatsu151.23%12.94%
tejun heotejun heo131.07%12.94%
andy lutomirskiandy lutomirski120.99%25.88%
adrien schildknechtadrien schildknecht60.49%12.94%
huang yinghuang ying50.41%12.94%
thomas gleixnerthomas gleixner50.41%38.82%
jan beulichjan beulich40.33%25.88%
steven rostedtsteven rostedt30.25%12.94%
kurt garloffkurt garloff30.25%12.94%
namhyung kimnamhyung kim30.25%12.94%
rusty russellrusty russell20.16%12.94%
christian borntraegerchristian borntraeger20.16%12.94%
prarit bhargavaprarit bhargava10.08%12.94%
frederic weisbeckerfrederic weisbecker10.08%12.94%
srikar dronamrajusrikar dronamraju10.08%12.94%
andrey ryabininandrey ryabinin10.08%12.94%
Total1215100.00%34100.00%
Directory: arch/x86/kernel